This invention pertains to the fields of solar thermal energy and solar thermophotovoltaics.
DESCRIPTION OF THE RELATED ART
Spectral control of the surface emissivity is essential in applications pertaining to concentrated solar thermal (CST) systems and solar thermophotovoltaic (TPV) systems because it enables high conversion efficiency. Ideally, said spectral control might employ thin-film structures which simultaneously function as (i) efficient broad-band absorbers of solar radiation in the spectral region 250 nm<λ<1 μm, (ii) extremely poor absorbers of any infrared radiation for λ>3.5 μm, and (iii) spectrally selective infrared emitters that can be tuned to emit in the 1.5 μm<λ<2.5 μm range, thus matching the bandgap of the particular TPVs employed.
Thin-film structures capable of accomplishing some of these requirements have been proposed, but none of them to date accomplishes all three at once.